Slope and fan deposition in deep-water turbidite systems, East Antarctica

摘要

Detailed seismic stratigraphic analysis of 2D reflection seismic data from the East Antarctic rifted continental margin provides an ancient analogue for turbidity fan systems at high-latitude margins. Reflector sequences characteristic of turbidity flow channel migration and aggradation are identified, along with other depositional elements integral to the understanding of deep-water deposition, such as channel levees, splays and wavy bedforms. Wavy bedforms are contrasted with slump-related features, which although present do not explain the morphological features interpreted here as sediment waves. Slump-related features suggest, qualitatively, a relationship between a basal detachment layer and a widespread bottom-simulating reflector. The influence of the initial morphology on slope deposition and distributary patterns for turbidite deposits is clear in these data. Healed-slope accommodation on an above-grade slope is evident in seismic profiles. Ponded and/or healed-slope accommodation is associated with pre-existing bathymetric highs, interpreted as rift-related, serpentinised, peridotite ridges.